Refrigerating system



Patented Jan. 12, 1932?- UNITED STATES PATENT; oI-unc-E LLOYD G. OOIEMA N, OF FLINT, MICHIGAN, ASSIGNOIR'- TO COPEMAN LABORATORIES,

COMPANY, OF FLINT, MICHIGAN, A. CORPORATION MICHIGAN REFRIGERATING SYSTEM This invention relates to a refrigerating system, and has'to do particularly with a novel method and apparatus for utilizing dry ice or solidified CO as a refrigerating medium and source of power.

The low temperatures resulting from the physical phenomena in the changing of the solidified CO backto the gaseous state are universally made use of in many ways. The present invention not only makes use of such low temperatures in the evaporation of dry ice' but also makes direct use of the gases produced by the direct change from a solid to a gas, in materially assisting in the transfer of heat to suitable remotely positioned cooling units or devices.

More specifically, the present invention resides in the provision of a complete automatic refrigerating unitwherein a cake of solidified CO serves as the sole refrigerating me-' dium. The circulatingbrine is. brought to very low temperatures by contact with the solid CO and then conducted to the cooling unit much the same as in a standard mechanically operated refrigerating system. This circulation of the brine is accelerated and made absolutely positive by utilizing the gases evolved in the evaporation of the solid 2- Other features reside in the manner of introducing the CO gas into the brine to cause positive circulation thereof, together with details of the system and structure as will be more clearly brought out in the specification and claims.

In the drawings Fig. 1 is a vertical sectional view of oneform of structure embodying the present invention, a portion thereof being somewhat diagrammatic.

Fig. 2 is an enlarged fragmentary view'of a portion of the air pump or what might be termed an aspirating device.

While the present invention should have an almost universal use, it is particularly adapted at the present time for use in places where mechanical refrigeration cannot be depended upon, such as, for instance, in railway dining It is also invaluable for use in retailing and storing quicklyfrozen' foods.

Any suitable container and cooling unit may be utilized in carrying out the invention, and in the embodiment illustrated I have shown a. suitable containerl for receiving the cake 2 of solidified CO This container may be made of aluminum or other material of good conductivity. Suitable brine conducting coils 3 may be arranged within or in heat conducting relation to the container 1 but I preferably desire to position these coils 3 in direct contact with the gake of solid C0 2;

that is, the CO ice may be directly supported by the coils and/or positioned inside of the coils.

An annular receiver 4 preferably surrounds the container 1 and this receiver is adpted to contain a definite supply of brine 5. This brine may consist of calcium chloride or other substance having a relatively low freezing point. The coils 3 are directly connected to the supply of brine 5 and in turn conduct the brine to a suitable cooling unit which may be generally designated 6: It will be understood that this cooling unit may be positioned at any point adjacent to or remote from the main container 1, the point being that the refrigerated brine is conducted to a suitably designed and positioned cooling unit to accomplish the desired refri crating effect much the same as in any standard refrigerating system. In the particular embodiment shown, the cooling unit consists of what might be termed an ice maker or storage and dispensing cabinet for quickly frozen foods, in that a series of sharp freezing storage compartments 7 are surrounded by the cooling coils 8. If desired, the compartment in the brine receiver 4. A relatively small conduit 12 is positioned within the main container 1 and is adapted to conduct the evaporated CO under a slight pressure to a conduit 13 extending within the cylinder 9. To control the pressure and flow through this conduit 12 1 preferably provide a suitable valve 14 and a pressure relief valve 15. I have found from experiment that approximately ten pounds pressure gives the best results for a unit similar to the one shown in the drawings, with the result that all surplus pressure developed in the container 1 will be released by the valve 15.

The conduit 13 within the cylinder 9 is preferably provided with a series of laterally extending apertures 16, as best shown in Fig. 2. I have found that in a device of the type illustrated that a quarter-inch pipe 13 with six inches apart gives the best results. a By using the laterally arranged apertures 16, the CO gas under slight pressure will be discharged laterally to form gas pistons, such gas pistons .rising because of the relative specific gravity with the result that cylindrical slugs of brine are raised upwardly and intermittently discharged from the top of the brine conduit at the point 10. The discharged CO gases will pass upwardly through the top of the annular receiver 4 and may be conducted to the atmosphere in any suitable man- I ner, as by means of a suitable port or ports By using-a glass cylinder 9 I have found that by increasing the pressure within the cylinder 1, and hence in the conduit 12, the CO gas will be discharged upwardly in small streams through the brine instead of raising the brine itself; in other words, instead of forming complete gas pistons, the gases under the higher pressures merely cut their way through the brine and are discharged through the top of the conduit simply as gas.

In operation, the system having been filled with brine, the charge or cake of'solidified CO may be positioned within the container 1, the top 18 closed down and the insulated cover 19 positioned in place. As the brine will be initially 'at a relatively high temperature it will be obvious that the solid CO will start to evaporate with great rapidity, cooling the brine within the coils 3 to a very low temperature. Of course, this cooled brine tends to fiow towards the lower ends of the coils 8 but circulation is greatly accelerated by the pump action within the cylinder 9. As the CO evaporates a predetermined pressure will be maintained within the container 1 and this CO under the predetermined pressure is conducted through the coil 12 and into the apertured conduit 13. This CO under slight pressure will be discharged laterally from the apertures 16 to form gas pistons, as

best shown in Fig. 2. Due to the difierence the apertures 16 spaced approximately in specific gravity, these gas pistons will raise the separated slugs of brine upwardly and discharge the same out the top of the conduit at the point 10 much the same as if a reciprocating pump were being used.

With this positive circulation the entire refrigeratingsystem, or in other words, the

entire supply of brine will be gradually lowered to a temperaturesubstantially the same as that originally createdin the chamber 1 due to the evaporation of the solid C0 The constantly maintained supply of brine 5 around the outside of the container 1 will materially reduce any heattransfer from the container 1 with the result that once the system is lowered to the desired low temperature, the evaporation of the CO ice will be materially reduced. v

It will thus be seen that I have provided a positive refrigerant circulating system having no moving mechanical parts of any kind. A supply of CO ice suflicient to last some twenty-four to forty-eight hours may be initially placed within the unit with the result that low temperature refrigeration is positively obtained and maintained for a predetermined period. It will be understood that the Various details of construction may vary considerably and still come within the bounds of the present invention; the size and position of the conduit 12 may be varied and it may be found that the pump action within the cylinder 9 may be obtained in different ways than that disclosed. The essence of this part of the invention is the fact that evaporated CO is utilized to promote positive circulation of the brine.

It will further be understood that any convenient form of cooling unit may he used as the circulation of the brine permits the system to be adapted to any desired design of cooling unit or storage space. As the available commercial supply of solid CO is rapidly increasing and the cost of the same is just as rapidly decreasing, it will be obvious that quick freezing temperatures or at least temperatures suflicient to maintain quickly frozen foods in the proper state of preservation may be readily and easily obtained and at relatively small expense; especially as compared with the expensive refrigerating apparatus necessary to maintain relatively low temperatures.

It will be obvious that I am in no way limitup the system. However,-as long as positive between 30 and 40 F. below zero for a pev riod of approximately eight hours with thirty pounds of solid CO K e What I claim is: v 1. I A refrigerating system, comprising a container for receiving a charge of solid CO2,

refrigerant circulating means positioned in direct heat conducting relation with said solid CO said means extending to and forming a part of'a' cooling unit, means for' controlling the escape'of CO gas from said container,

and means for positively circulating the refrigerating medium in said circulating means. 2. A refrlgerating system, comprising a container for receiving a charge of solid CO2,

i tion with said solid CO said means extend= refrigerant containing and circulating means positioned in heat conducting relation with said container, said means extending to and forming a part of a cooling unit, means for controlling the escape of CO gas from said container to permit evaporation of said CO2 directly from a solid to a gas, and means for positively and continuously circulating the refrigerating medium through said first named means.

3. A refrigerating system, comprisin a container for receiving a charge of solid (J02, refrigerant circulating means positioned in directheat conducting relation with said CO container, said means extending to and form ing a part of a cooling unit, said container being constructed to permit change of said solid CO to a gas, and means for conducting such evaporated CO gases into the refrigerant stream to accelerate circulation thereof.

4. A refrigerant system, comprising a con- .tainer for receiving a charge of-solidcOz,

refrigerant circulatlng means for positioning the refrigerant 1n direct heat conductlng relaing to and forming a part of a cooling unit, and means actuated solely by the pressure developed by the changing of the solid CO2 to a gas for positively circulating refrigerant through the circulating means.

5. A refrigerating system, comprising a cooling unit, means for conducting refrigerant to and from said cooling unit, means of the type adapted to change directly from a solid state to agaseous state'to produce a refrigerating effect positioned in constant and direct heat conducting relation withaportion of the supply of refrigerant, and means actuated by the gas produced by said charge for causing positive circulation of the refrigerant through the cooling unit.

6. Refrigerating apparatus comprisin a refrigerant circulating system, a solid 0 chamber, a conduit connected into the said chamber for conducting the evaporated CO into the refrigerant system, said conduit havin one or more apertures for discharging the C5 gases into the refrigerant stream to effect positive circulation thereof.

7. Refrigerating apparatus of the ty e described, comprising a refrigerant circu ating system, a solid CO chamber, a conduit connected into the said chamber for conducting the' evaporated CO into a conduit forming part of the refrigerant system, said (JO and refrigerant conduits being positioned substantially vertically, and one or more apertures extending laterally from said CO conduit for projecting a charge of gas into the refrigerant stream to cause positive circulation thereof.

8: A refrigerating system comprising a solid CO container, brine coils passing in heat conducting relation to said containerand extending into and formin apart of a cooling unit, means for maintaining a predetermined pressure within the container and means for conducting the CO gases under said predetermined pressure into the brine in the form of gas pistons, said gas pistons risin and carrying along slugs of brine where y to cause positive and continuous circulation of the brine during evaporation of the solid C02.

9. A refrigerating system comprising a cooling unit, a solid CO container, a brine receiver adjacent the container, brine coils passing in heat conducting relation to said container and extending into and forming a part of the cooling unit, means for maintaining a predetermined pressure within the con-' tainer and means for 'conducting the (10 gases under said predetermined pressure into the brine in the form of gas pistons,said pistons rising and carrying along slu of brine whereby to cause positive and continuous circulation of the brine during evaporation of the solid CO 10. Amethod of refri eration which consists in chilling a brine y bringing it into heat exchange with a body of solid carbondioxide, circulating the. brine thus chilled in heat exchange relation to the substanceto be refrigerated, bringing the brine thus warmed into heat exchange relation with the solid carbon-dioxide and causing the brine to thus circulate by injecting into said brine some carbon-dioxide gas evaporatedfrom said body of solid carbon dioxide.

. 11. A refrigerating systemromprising a solid CO container, a brine receiver surrounding said container, brine circulating means passing in heat conducting relation to said container and extending into and forming a part of a-cooling unit, means for maintaining a predetermined pressure Within the CO container and means for conducting the CO gases under said predetermined pressure into the brine in the form of gas pistons,

slugs of brine into the brine receiver whereby to cause positive and continuous circulation of the brine during evaporation of the solid CO 12. A method of refrigerating with solid CO as the cold producing medium which comprises providing a cyclic path for brine, cooling the brine by evaporation of the solid CO and circulating the brine in its cyclic path by the gas power produced by the evaporation of the solid CO 13. A refrigerating system, comprising a solid CO container, abrine receiver surrounding said container, brine circulating means positioned in direct heat exchange relation to said container and extending into and forming a part of a cooling unit, means actuated by the gas evaporated from said body of solid CO for positively circulating the brine and causing the brine to pass into direct heat exchange relation with the CO container and then through the cooling unit, and means for controlling the flow of gas evaporated from said body of solid CO to regulate the circulation of refrigerant by said gas.

14. A method of refrigeration which consists in chilling a brine by bringing it into heat exchange relation with a body of solid carbon dioxide, circulating the brine thus chilled in heat exchange relation to the substance to be refrigerated, bringing the brine thus warmed into heat exchange relation with the solid carbon dioxide and utilizing the potential energy of the carbon dioxide gas evaporated from said body of solid carbon dioxide to circulate the brine.

15. A refrigerating system, comprising a container for receiving a charge of solid CO refrigerant circulating means positioned in direct heat conducting relation with said con tainer, said means extending to and. forming a part of a cooling unit, means for controlling the pressure within the container so as to maintain the evaporated CO in gaseous form,

meansfor positively circulating the refrigerating medium in said circulating means, and means for controlling the rate of said circulation.

16. A refrigerating system, comprising a container for receiving a charge of solid CO refrigerant circulating means positioned in heat conducting relation to said container, said means conducting the cooled refrigerant into heat exchange relation with a cooling unit, said container being constructed to maintain all the evaporated CO in the container as a gas, means for positively circulating the refrigerant medium in said circulating means, and. means for controlling the rate of said circulation.-

,17. A refrigerating system, comprising a cooling unit to maintain a certain predetermined temperature, a container for receiving a charge of solidified 00 a supply of brine, means Ior conducting'the brine into direct heat exchange relation with said charge of CO and into direct heat exchange relation with said cooling unit, said container being constructed to so control the pressure in the container as to maintain the evaporated CO as a gas, and means for producing a positive circulation of brine throughout the system, said means being regulable to control the rate of circulation of said brine.

18. A refrigerating unit comprising a casing, a cooling unit within the casing for receiving a substance to be cooled, a container within the casing for receiving a charge of solid CO a supply of non-volatile liquid, means for conducting the liquid into wiping contact with the walls of said container and into heat exchange relation with the cooling unit, means for positively circulating the liquid in the system, and means for regulating the rate of said circulation to control the degree of said wiping action and the temperature of said cooling unit.

In testimony whereof I affix my signature. 

